1. Technical Field
The present invention relates generally to a power converter apparatus equipped with a series-connected assembly of a first current flow controlling component which has an open/close function to open or close a current flow path and a second current flow controlling component which has at least one of the open/close function and a rectifying function to permit a flow of current only in one direction, and an inductor coupled to a joint of the first and second current flow controlling components.
2. Background Art
Power converters which are equipped with magnetic parts and serve as a power supply have been required to be reduced in size upon recent request to downsize electronic equipment. Usually, the magnetic parts that are passive components occupy a considerable part of the size of the power converter. The downsizing of the power converter, therefore, requires the reduction in size of the passive components. This requires the need for increasing the switching frequency in the power converter, but results in an increase in switching loss, which leads to a decrease in efficiency in operation of the power converter. The switching loss is generally quantified by a time integral of a product of a potential difference between ends of a current path in which a switching device is disposed and an electric current flowing through the current path upon an on/off operation of the switching device.
In order to decrease the switching loss, Japanese Patent First Publication No. 2001-178116 teaches use of a series-connected assembly of a diode and a snubber capacitor which are coupled together in series and also in parallel to a switching device in a step-up chopper circuit. Specifically, the voltage developed across the switching device when turned off is restricted by a change in voltage charged in the snubber capacitor, which will lead to decrease the switching loss.
The above prior art system, however, has the problem that it is impossible to decrease the switching loss when the switching device is turned on.